[Zuk Z1 Android Development] zombiezoom:
USB-OTG works in unofficial CM13 by MrColdbird, I confirm it doesn't work in TWRP though.

Here's the requested log:

u0_a104@ham:/ $ mount
rootfs on / type rootfs (ro,seclabel,noatime,nodiratime)
tmpfs on /dev type tmpfs (rw,seclabel,nosuid,noatime,nodiratime,size=1450720k,nr_inodes=113520,mode=755)
devpts on /dev/pts type devpts (rw,seclabel,noatime,nodiratime,mode=600)
none on /dev/memcg type cgroup (rw,noatime,nodiratime,memory)
none on /dev/cpuctl type cgroup (rw,noatime,nodiratime,cpu)
proc on /proc type proc (rw,noatime,nodiratime)
sysfs on /sys type sysfs (rw,seclabel,noatime,nodiratime)
selinuxfs on /sys/fs/selinux type selinuxfs (rw,noatime,nodiratime)
debugfs on /sys/kernel/debug type debugfs (rw,seclabel,noatime,nodiratime)
none on /sys/fs/cgroup type tmpfs (rw,seclabel,noatime,nodiratime,size=1450720k,nr_inodes=113520,mode=750,gid=1000)
none on /sys/fs/cgroup/memory type cgroup (rw,noatime,nodiratime,memory)
none on /sys/fs/cgroup/bfqio type cgroup (rw,noatime,nodiratime,bfqio)
none on /acct type cgroup (rw,noatime,nodiratime,cpuacct)
tmpfs on /mnt type tmpfs (rw,seclabel,noatime,nodiratime,size=1450720k,nr_inodes=113520,mode=755,gid=1000)/dev/fuse on /mnt/runtime/default/emulated type fuse (rw,nosuid,nodev,noexec,noatime,nodiratime,user_id=1023,group_id=1023,default_permissions,allow_other)
/dev/fuse on /mnt/runtime/read/emulated type fuse (rw,nosuid,nodev,noexec,noatime,nodiratime,user_id=1023,group_id=1023,default_permissions,allow_other)
/dev/fuse on /mnt/runtime/write/emulated type fuse (rw,nosuid,nodev,noexec,noatime,nodiratime,user_id=1023,group_id=1023,default_permissions,allow_other)
/dev/block/bootdevice/by-name/system on /system type ext4 (ro,seclabel,noatime,nodiratime,discard,data=ordered)
/dev/block/bootdevice/by-name/userdata on /data type ext4 (rw,seclabel,nosuid,nodev,noatime,nodiratime,discard,noauto_da_alloc,data=ordered)
/dev/block/bootdevice/by-name/cache on /cache type ext4 (rw,seclabel,nosuid,nodev,noatime,nodiratime,discard,noauto_da_alloc,data=ordered)
/dev/block/bootdevice/by-name/persist on /persist type ext4 (rw,seclabel,nosuid,nodev,noatime,nodiratime,discard,noauto_da_alloc,data=ordered)
/dev/block/bootdevice/by-name/mrd on /oem type ext4 (rw,context=u:object_r:oemfs:s0,nosuid,nodev,noatime,nodiratime,discard,noauto_da_alloc,data=ordered)
/dev/block/bootdevice/by-name/modem on /firmware type vfat (ro,context=u:object_r:firmware_file:s0,noatime,nodiratime,uid=1000,gid=1000,fmask=0337,dmask=0227,codepage=cp437,iocharset=iso8859-1,shortname=lower,errors=remount-ro)
tmpfs on /storage type tmpfs (rw,seclabel,noatime,nodiratime,size=1450720k,nr_inodes=113520,mode=755,gid=1000)
/dev/fuse on /storage/emulated type fuse (rw,nosuid,nodev,noexec,noatime,nodiratime,user_id=1023,group_id=1023,default_permissions,allow_other)
tmpfs on /storage/self type tmpfs (rw,seclabel,noatime,nodiratime,size=1450720k,nr_inodes=113520,mode=755,gid=1000)
/dev/block/vold/public:8_1 on /mnt/media_rw/D0F2-DEAC type vfat (rw,dirsync,nosuid,nodev,noexec,noatime,nodiratime,uid=1023,gid=1023,fmask=0007,dmask=0007,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)
u0_a104@ham:/ $

As you can see, it gets mounted at: /mnt/media_rw/